Fastener panel construction

ABSTRACT

Apparatus for fabricating structural building units from a pair of panels and a plurality of stringer members including a framework for positioning the panels in a spaced-apart relationship and for supporting stringer members longitudinally and in spaced-apart position therebetween. The panels and stringers are advanced in incremental steps through special clamping and fastening means having a plurality of automatic fastening machines for driving fasteners through the panels into the stringer members in a first section. The panels and stringers are automatically indexed forwardly and a second section is fixed in a similar manner. The advancing and fastening steps are repeated automatically until the entire assembly is secured in like fashion to thereby provide a rigid unit. Insulating material may be positioned between the panels and stringers to provide an insulated panel for exterior wall construction.

United States Patent 1191 Kay FASTENER PANEL CONSTRUCTION Charles Kay, Alto, Mich.

George D. Baldwin, Grand Rapids, Mich.

Sept. 11, 1972 Inventor:

Assignee:

Filed:

Appl. No.:

US. Cl 227/40, 227/99, 227/152 Int. Cl B27f 7/02 Field of Search 227/29, 30, 39, 40, 99,

References Cited UNITED STATES PATENTS 5/1963 McRae et a1. 227/103 x 1/1970 Martin 227/103 x 7/1973 Bowers, .lr. 227/100 Primary Examiner-Granville Y. Custer, Jr. Attorney, Agent, or Firm-Price, l-leneveld, l-luezenga & Cooper 14 1 Apr. 16, 1974 [57] ABSTRACT Apparatus for fabricating structural building units from a pair of panels and a plurality of stringer members including a framework for positioning the panels in a spaced-apart relationship and for supporting stringer members longitudinally and in spaced-apart position therebetween. The panels and stringers are advanced in incremental steps through special clamping and fastening means having a plurality of automatic fastening machines for driving fasteners through the panels into the stringer members in a first section. The panels and stringers are automatically indexed forwardly and a second section is fixed in a similar manner. The advancing and fastening steps are repeated automatically until the entire assembly is secured in like fashion to thereby provide a rigid unit. Insulating material may be positioned between the panels and stringers to provide an insulated panel for exterior wall construction.

15 Claims, 8 Drawing Figures 1/. P l Z M 1 7 81 N l/ 13 R11 g s S... t C.

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PATENTEDAPR 1 6 m4 SHEET 1 [IF 3 PATENTED APRI 61574 SHEET 2 BF 3 m w-u 9 W M I HIHIIF EILIEEIQ 3L1 flTQ 3 378 Mm E q wu i E i PATENTEU APR] 61 5M SHEET -3 OF 3 FASTENER PANEL CONSTRUCTION BACKGROUND OF THE INVENTION This invention relates to apparatus for manufacturing structural building units and more particularly, to apparatus for assembling a pair of panels and a plurality of longitudinally extending spaced-apart stringer members into unitary structural building units. In my prior patents, I have provided various methods and apparatus for the fabrication of building construction units. Specifically, U.S. Pat. No. 3,286,428, issued Nov. 22, 1966, describes the assembly of individual building block units. U.S. Pat. No. 3,574,253, issued Apr. 13 197], discloses apparatus for assembling the building block units and U.S. Pat. No. 3,603,060, issued Sept. 7, I971, is particularly adaptable to large panel construction, as for example, four feet by 8 feet.

Each of the above patents disclose various methods and apparatus for inserting metal connecting plates into and between slabs or panels to form structural building units. The units described therein are extremely rigid and stable; however, each of the constructions require special connector plates which are forced into the panels and require a substantial amount of special machinery. In some cases, the panels must be cut or grooved such that the connector plates can be inserted therein. In other cases where extremely large panels are provided, elongated metal connector plates extend substantially the full length or width of the panel and, accordingly, special power insertion means must be provided for inserting the plates.

SUMMARY OF THE INVENTION 4 and simultaneously drive fasteners through the panels into the stringers in a first zone. Advancing means are provided to move the panels and stringers in incremental steps a predetermined distance and to hold them in position while additional fasteners are inserted in the next zone. Once the apparatus is set into operation, the clamping, fastening, and advancing movements continue automatically until the panels are secured to the stringers along the entire length to provide a rigid structural building unit.

In a preferred embodiment of the invention, the stringer members are conventional two-by-fours and stapling machines are arranged in horizontal and vertical rows to drive staples through the panels and into the stringers to secure the panels to the stringers. Selected ones of the stapling machines may be rendered inoperative in horizontal or vertical rows such that angle cut panels, as used in the gable end of housing construction, may be assembled. The present invention is also adapted to utilize a wide range of materials, from prefinished smooth plywood and roughsawn cedar which may be coated with stone and brick aggregate, or laminated with plastic and metal finishes. The machine is flexible and swings apart to accept various widths of materials such that the panels may be fastened to stringer members of variable sizes.

Insulating material may be placed between the panels and stringer members prior to the fastening thereof so that the unitized panels are discharged from the machine, insulated, and fastened to the stringer members on predetermined centers. The panels thus constructed can be used for exterior and/or interior walls, floors, ceilings, and roofs. Framing for doors and windows may also be stapled into position between the panels by means of adjustably mounted fastening machines which may be selectively operated to fasten such framing therein.

Other unique features and the many advantages of the present invention will become readily apparent to those skilled in the art upon reading the following disclosure and with reference to the accompanying drawmgs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the fabricating machine of the present invention;

FIG. 2 is a side elevational view of the fabricating machine shown in FIG. 1;

FIG. 3 is a sectional top view of the apparatus viewed along the plane III-III in FIG. 2;

FIG. 4 is a view of the inlet end of the fabricating machine as viewed along the plane IV-IV in FIG. 2;

FIG. 5 is a partial perspective view of the outlet end of the apparatus with the clamping and fastening means shown in an open position and a first panel and stringer positioned therein with details omitted for clarity;

FIG. 6 is a perspective view illustrating the fastener driving means and the mounting thereof on the supporting framework;

FIG. 7 is an enlarged, partially sectional view taken along the plane 'VIIVII OF FIG. 2 illustrating the panel-advancing mechanism; and

FIG. 8 illustrates the outlet end of the apparatus as viewed along the plane V-IIIVIII of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and in particular to FIGS. I through 3, the apparatus for forming prefabricated structural building units is generally designated by the numeral 10 and includes a supporting framework 12 having a pair of elongated base support rails 14 extending along its length. A plurality of transverse support plates 16 are positioned at the ends of the support rails and include leveling pads 17 at their outer ends so that the machine may be mounted in a flat and level position. Upright post members 18 extend from base support rails 14 to support an elongated upper support rail 20 which runs the length of the apparatus and is centrally positioned with respect to the base support rails 14. An upper frontal cross arm 22 extends transverse to support rail 20 and pivotally mounts a first panel clamping means 24 at one side of the apparatus. A similar panel clamping means 26 is positioned opposite to and is cooperable with the first to secure a panel therebetween as will be further described hereinafter.

A carriage 28 is mounted for reciprocal movement along base support rails 14 to advance the panels in a series of steps between panel clamping means 24 and 26. A roller conveyor assembly 30 is also positioned between rails 14 to support the panels as they are advanced through the machine. The outlet end of the apparatus designated by the numeral 31, abuts an external roller conveyor 32 upon which the completed building unit is moved away.

The structural units formed by this invention comprise a pair of large individual panels P interconnected by elongated stringer members S (FIGS. 1, 3, and 5). The panels are usually of wood and preferably of standard dimension. The panels are connected to the stringer members, such as wooden two-by-four studs, by means of staples or the like which are driven through the panels and into the stringers by banks of stapling machines mounted on the panel clamping means.

While the invention will be hereinafter described with reference to standard 4-by-8 or 4-by-l 2 foot panels, it will be understood that the length of the completed panel is limited only by the length of the available raw materials. Unitized panels of 24 feet in length may be constructed by using standard 24 foot stringer members and two l2-foot panels on each side or alternately through the use of three 8foot panels. In the absence of readily available panels, of for example 12 feet in length, two 8-foot panels may be combined with two 4-foot panels to form a 12-foot unit. In any event, when combining several panels on elongated stringers, auxili ary stapling devices 34-may be positioned at a convenient distance along the length of the machine, on each side thereof, to drive a single staple through the additional panel into the stringer so that it is held in position and pulled through the clamping means with a first constructed portion of a unitized panel. Alternately, another conveyor may be incorporated with conveyor 30 below the panels to engage the ends of the additional panel section to move the additional section together with the first section into and through the panel clamping means.

It will also be understood that angle cut panels may be assembled by the present apparatus by simply deactivating one or a number of the staple driving apparatuses on panel clamping means 24 and 26. Similarly, vertically adjustable rows of stapling devices may be provided on the clamping means to fix door headers, window framing and the like in position between the panels as they are assembled.

Referring additionally to FIGS. 4 and 5, panel members P and stringers S are shown positioned in framework l2 prior to the actual fastening operation. Stringer supporting members 36 extend laterally along the length of the framework between rear upright support 18 and at the inlet end 37 forwardly toward the panel clamping means at outlet end 31. The stringer supports are positioned to hold the stringers in a predetermined spaced-apart position. In conventional homebuilding construction, the standard spacing is 18 inches between centers. The uppermost stringer is preferably arranged to extend from between the panels approximately one-halfits thickness. On the opposite, i.e., lowermost edge, the panels protrude overlappingly beyond the lowermost stringer a like amount to form a recess therebetween. Then the extending stringer on one structural unit can fit in dovetail fashion in the recess on an adjacent structural unit.

Stringer supports 36 are fixed in position by vertically extending support plates 38 secured to upper support rail and extending downwardly with the lower ends fixed between lower support rails 14. Conventional fastening means such as screws or rivets 40 secure the stringer support members to support plates 38.

Stop abutment members 42 are positioned along an upper flange on each stringer support 36 to locate and position the end of the stringers placed thereon. A series of holes 44 (FIG. 3) are provided along the length of the stringer support members on the upper portion of the flange to receive the stop members at various positions along the length. The holes or openings 44 for the stop abutment members are preferably positioned to receive abutment members 42 at predetermined standard dimensions, i.e., 8, l2, 16, 20 and 24 foot intervals. The panels are then positioned in abutting relationship to the stringers on either side of the stringer support members.

As illustrated in FIG. 1, an insulating material, preferably in the form of insulation batts, may be placed between the stringers before the panels are positioned in the framework to thereby provide an insulated, unitized construction. Insulated units are normally used for exterior wall construction whereas units for interior walls may be fabricated without the insulating material.

When the panels and stringers are positioned in the frame, the lower edges of the panels are supported on roller conveyor 30 for movement along the length of the apparatus toward and through the outlet end 31 as the actual fastening operation is performed. The lower front portions of the panels rest in and are supported on carriage assembly 28.

Referring additionally to FIG. 7, carriage assembly 28 includes a base 46 mounted for sliding movement along support rails 14. Rollers 48 fixed on the lower side of base 46 ride on a pair of tracks 50 fixed to the inner portions of support rails 14 and extend from the outlet end of the apparatus along the length of the panel-clamping means 24 and 26. The carriage is shiftable between retracted and advanced positions along rails 14 and tracks 50 by an air cylinder 52 having an extendable and retractable piston rod 54 therein. The cylinder is fixed at the side of the framework on the outside of the base support rails 14 (FIGS. 2 and 6). The end of piston rod 54 is fixed to the carriage.

A pair of cooperable air cylinders 56 secured on the upper portion of the base include piston rods 58 movable toward each other in a direction transverse to movement of the carriage. A pair of positioning blocks 60 secured to the base extend upwardly a slight distance. The positioning blocks are spaced apart, at their outer faces, a distance corresponding to the width of the stringer members which are to be secured between the panels. The positioning blocks may be adjusted to accommodate stringer members of various width. Cooperating pressure feet 62 fixed to the ends of the piston rods 58 are adapted, when cylinders 56 are actuated, to secure the panels against positioning blocks 60.

When piston rod 54 on cylinder 52 is retracted, the carriage assembly retracts. The panels are advanced by actuating cylinders 56 thereby securing the panels between pressure feet 62 and blocks 60. Cylinder 52 is subsequently actuated to extend piston rod 54 moving the carriage and the panels held thereon forwardly along support rails 14 on tracks 50. Accordingly, the panels move toward the outlet end of the framework through panel-clamping means 24 and 26.

Referring to FIGS. 3 and 8, panel-clamping means 24 and 26 include a pair of opposed plate members 25 and 27. These are shiftable toward and away from each other to receive and secure a pair of panels and stringer members while fastening operations are performed. Plates 25 and 27 are basically identical in construction, although plate 25 is supported in a hinged gate-like frame structure 65 (FIG. 5) such that it may be opened for access and ease in loading of the panels and string ers into the apparatus. Plate 27 is mounted on the fixed framework. As shown in FIGS. 5 and 6, each plate has a plurality of air-actuated stapling devices 64 arranged in horizontal and vertical rows. The stapling machines are of conventional construction and include an elongated magazine 66 to hold a quantity of staples. In the preferred embodiment of the invention, a staple having a two-inch length is utilized to secure a pair of threequarter inch thick panels to two-by-four stringer members.

Plates 25 and 27 are mounted on the framework by a pivoted linking mechanism which includes a pair of shafts 68 extending vertically adjacent the sides of plate members 25 and 27. Shafts 68 are rotatably mounted in pillow blocks 70 on the outer faces of plates 25 and 27. Arm members 72 are connected to the upper and lower ends of shafts 68 at one end of the arm. The opposite ends of arms 72 are mounted to the framework in bearings on upper and lower support cross members 74 and 76 respectively. Air cylinders 80 fixed to the supporting framework each have an extendable piston rod 82 connected at their outermost end to plates 24 and 26. When cylinders 80 are activated, extension of piston rods 82 causes the plates to pivot about shafts 68 and causes arm members 72 to pivot about cross members 74 and 76, to thereby shift the plates into engagement with the panels and to press the panels against the stringer members. Staplers 64 are then activated to simultaneously drive a plurality of staples through the panels and into the stringers. 7

As illustrated in FIGS. 1 and 5, plate 25 is mounted in gate-like frame 65 such that it may be opened for access and ease in loading-the panels and stringers. Upright support post 18' at the outlet end of the apparatus has a shaft 84 extending from the ends thereof and mounted in bearings 86 supported by the main frame structure, so that the gate may be opened as shown in FIG. 5. The gate is of welded construction and provides a support for plate 25 on upper cross member 74' and lower cross member 76. It also includes a vertical frame member 88. A roller 90 positioned at the bottom of vertical frame member 88 supports the gate when opened. Roller 90 rolls on transverse plate 16' (FIG. 1). When closed, the gate is held in position by a latch actuator 98 operable to drive a hydraulically actuated latch pin 102 into engagement with a latch plate 104 (FIG. 5) located in base support rail 14.

The interior facing surfaces of plates 25 and 27 are identical. Openings 92 in the plates are in alignment with stapling machines 64 through which the staples are driven to secure the panels together. An elongated slot 94 is provided at the leading edge of the plates to accommodate a vertical row of staplers 64 adjustably mounted on the plates. The adjustably mounted staplers are provided and actuated to accommodate the stapling of door headers and window framing structures which may be included in the unitized panel as it is constructed.

Suitable valve means are connected in pressure lines 96 directed to each of the stapling machines so that selected staplers may be rendered inoperative to accommodate window and door cut outs and the like. Similarly, selected staplers may be rendered inoperative to accommodate angle-cut panels. Various state of the art control devices may be included in the control panel 100 for the apparatus to program the activation or deactivation of selected stapler devices depending upon the particular panel under construction. Typically, window framing and header members are positioned transverse to the stringer members and may be positioned therein between the stringers before the panels are placed in position on the framework on opposite sides of the stringer support members.

OPERATION Assuming that the apparatus is empty and at rest, carriage mechanism 28 is in its retracted position and gate 65 of outlet end 31 is open a slight distance. A plurality of stringer members S are then positioned on stringer supports 36 such that their rearward facing ends abut stop members 42 positioned on the stringer support members. A first panel is rolled into position from inlet end 37 of the apparatus on rollers 30 until it is positioned approximately as shown in FIG. 5 with its forward edge adjacent the outlet end of the machine. Any insulating material I (FIG. l) is positioned between the stringers and the second panel is rolled into position adjacent the stringers on the opposite side and in alignment with the first-positioned panel. Gate 65 is then closed and latched by operation of latch actuator mechanism 98 causing latch pin 102 to engage latch plate 104. Suitable pneumatic mechanisms operating through control panel 100 include timing mechanisms to operate the various actuators and staplers in a predetermined sequence. Once the gate is closed and the apparatus is set into operation, actuators are energized causing plates 25 and 27 to tightly compress panels P into aligned engagement with stringer members S. Simultaneously, staplers 64 are energized and drive a plurality of staples through the panels into the stringer members. After a first series of staples are driven through the panels, actuator 80 releases, drawing plates 7 25 and 27 back from the panels. Simultaneously, actuators 56 on carriage 28 are energized to fix the panels between pressure feet 62 and blocks 60 on the carriage. As actuators 56 are engaged, pressure is applied to actuator 52, causing piston rod 54 to extend and thereby shift the carriage and the panels secured thereto through the open plates 25 and 27 outwardly and through the outlet end of the apparatus a predetermined distance so that the space between each horizontal row of staples on the completed panel will be equal. Actuators 80 are again engaged closing plates 25 and 27, and the carriage moves back to its retracted position. A second series of staples is then driven through the panels into the stringer members, and the above cycle is repeated. This cycle of operation including clamping, stapling, releasing, and advancing repeats itself a desired number of times until the entire structure has passed through the outlet end and the formed unit is completed. The completed unit is then moved away from the apparatus on conveyor assembly 32 and the apparatus is ready for recycling.

While a preferred embodiment of the invention has been illustrated, it will be recognized that other modifications of the invention incorporating the teachings hereof may be readily made in light of this disclosure. Accordingly, all modifications embodying the principles thereof are to be considered as included in the appended claims unless these claims by their language expressly state otherwise.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for fabricating structural building units from panels and a plurality of stringer members comprising:

supporting means for holding a pair of panels in spaced relationship;

stringer supporting means for holding a plurality of stringers in predetermined spaced positions between said panels;

clamping means adjacent said panel-supporting means to secure said panels in abutment with said stringer members; and

fastener driving means mounted on said clamping means for simultaneously driving a plurality of fasteners into said panels and said stringer members to secure said panels to said stringers and thereby form a unitized structural building unit.

2. The apparatus as defined in claim 1 and further including incremental advancing means associated with said panel-supporting means to move said panels and said stringers through said clamping means in incremental steps, said clamping means being releasable from clamping engagement with said panels when said advancing means advances said panels.

3. The apparatus as defined in claim 1 wherein said panel-supporting means includes an elongated framework having an inlet end and an outlet end, said clamping means is positioned at said outlet end and said stringer supporting means extends from said inlet end along said frame toward said clamping means.

4. The apparatus as defined in claim 1 wherein said clamping means is shiftable between panel-engaging position and a released position and further including actuator means on said frame and said clamping means for shifting said clamping means between said positions; and means operating said fastener driving means when said clamping means is in said panel-engaging position.

5. The apparatus as defined in claim 4 wherein said clamping means includes a pair of plate members pivotally mounted on said frame, said plate members being adapted to shift toward and away from each other to secure said panels and stringer members therebetween.

6. The apparatus as defined in claim 5 wherein said fastener driving means includes a plurality of stapling machines mounted on said plate members, said stapling machines being positioned and adapted to simultaneously drive a plurality of staples into said panels and said stringers when said plate members are shifted toward each other.

7. The apparatus as defined in claim 2 wherein said fastener driving means includes a plurality of stapling heads arranged in aligned rows on said clamping means on opposite sides of said panels and in alignment with said stringers, each said driving means being adapted to simultaneously drive staples into said panels and said stringers to thereby secure said panels to said stringers.

8. The apparatus as defined in claim 7 wherein said advancing means includes a carriage mounted for reciprocal movement on said panel-supporting means; means for reciprocating said carriage, and means on said carriage for engaging said panels, said reciprocating means being adapted to shift said carriage and said panels thereon a predetermined distance through said clamping means when said clamping means is released.

9. The apparatus as defined in claim 8 wherein said reciprocating means includes a first fluid pressureresponsive actuator member having an extendable and retractable piston rod therein, one of said cylinder and said piston rod being fixed to said panel-supporting means and the other being fixed to said carriage.

10. The apparatus as defined in claim 9 wherein said means for engaging said panels includes a pair of second pressure-responsive actuator members on said carriage shiftable into panel-engaging position when said first fluid pressure actuator advances said panels through said clamping means.

11. The apparatus as defined in claim 3 and wherein said advancing means is adapted to move said panels and said stringers from said inlet end toward said outlet end through said clamping means in incremental steps.

12. In an apparatus for forming structural building units from a pair of spaced-apart panelsand a plurality of spaced-apart stringer members positioned between the panels, the improvement comprising:

means for supporting a pair of panels in a spacedapart position;

means for supporting a plurality of stringer members between said panels;

fastener driving means adjacent said panel-support means;

releasable holding means adapted to hold said panels in abutting relationship with said stringer members, said fastener driving means adapted to drive fastening means at predetermined positions through said panels into said stringer members when held by said holding means; and

panel-advancing means for advancing said panels and stringers a predetermined distance through said releasable holding means when said holding means is released.

13. An apparatus as defined in claim 12 wherein said releasable holding means comprises:

a pair of shiftable plate members mounted in a framework;

linkage means mounting said plate members for reciprocating movement; and

actuator means connected to said plate members and said framework for moving said plate members toward and away from each other to secure said panels therebetween.

14. The apparatus as defined in claim 13 and further including positioning means on said stringer support means; and means on said stringer support means and said positioning means for adjustably mounting same whereby said apparatus can be adapted to accommodate panels and stringer members of varying size.

15. The apparatus as defined in claim 14 and further including auxiliary stapling means on said frame positioned adjacent said positioning means for securing a second pair of spaced-apart panels to a first plurality of stringer members when said stringer members exceed the length of said first-mentioned panels whereby said first-mentioned and said second spaced-apart panels will move together through. said clamping and said fastening means to thereby form an elongated structural building unit. 

1. Apparatus for fabricating structural building units from panels and a plurality of stringer members comprising: supporting means for holding a pair of panels in spaced relationship; stringer supporting means for holding a plurality of stringers in predetermined spaced positions between said panels; clamping means adjacent said panel-supporting means to secure said panels in abutment with said stringer members; and fastener driving means mounted on said clamping means for simultaneously driving a plurality of fasteners into said panels and said stringer members to secure said panels to said stringers and thereby form a unitized structural building unit.
 2. The apparatus as defined in claim 1 and further including incremental advancing means associated with said panel-supporting means to move said panels and said stringers through said clamping means in incremental steps, said clamping means being releasable from clamping engagement with said panels when said advancing means advances said panels.
 3. The apparatus as defined in claim 1 wherein said panel-supporting means includes an elongated framework having an inlet end and an outlet end, said clamping means is positioned at said outlet end and said stringer supporting means extends from said inlet end along said frame toward said clamping means.
 4. The apparatus as defined in claim 1 wherein said clamping means is shiftable between panel-engaging position and a released position and further including actuator means on said frame and said clamping means for shifting said clamping means between said positions; and means operating said fastener driving means when saiD clamping means is in said panel-engaging position.
 5. The apparatus as defined in claim 4 wherein said clamping means includes a pair of plate members pivotally mounted on said frame, said plate members being adapted to shift toward and away from each other to secure said panels and stringer members therebetween.
 6. The apparatus as defined in claim 5 wherein said fastener driving means includes a plurality of stapling machines mounted on said plate members, said stapling machines being positioned and adapted to simultaneously drive a plurality of staples into said panels and said stringers when said plate members are shifted toward each other.
 7. The apparatus as defined in claim 2 wherein said fastener driving means includes a plurality of stapling heads arranged in aligned rows on said clamping means on opposite sides of said panels and in alignment with said stringers, each said driving means being adapted to simultaneously drive staples into said panels and said stringers to thereby secure said panels to said stringers.
 8. The apparatus as defined in claim 7 wherein said advancing means includes a carriage mounted for reciprocal movement on said panel-supporting means; means for reciprocating said carriage, and means on said carriage for engaging said panels, said reciprocating means being adapted to shift said carriage and said panels thereon a predetermined distance through said clamping means when said clamping means is released.
 9. The apparatus as defined in claim 8 wherein said reciprocating means includes a first fluid pressure-responsive actuator member having an extendable and retractable piston rod therein, one of said cylinder and said piston rod being fixed to said panel-supporting means and the other being fixed to said carriage.
 10. The apparatus as defined in claim 9 wherein said means for engaging said panels includes a pair of second pressure-responsive actuator members on said carriage shiftable into panel-engaging position when said first fluid pressure actuator advances said panels through said clamping means.
 11. The apparatus as defined in claim 3 and wherein said advancing means is adapted to move said panels and said stringers from said inlet end toward said outlet end through said clamping means in incremental steps.
 12. In an apparatus for forming structural building units from a pair of spaced-apart panels and a plurality of spaced-apart stringer members positioned between the panels, the improvement comprising: means for supporting a pair of panels in a spaced-apart position; means for supporting a plurality of stringer members between said panels; fastener driving means adjacent said panel-support means; releasable holding means adapted to hold said panels in abutting relationship with said stringer members, said fastener driving means adapted to drive fastening means at predetermined positions through said panels into said stringer members when held by said holding means; and panel-advancing means for advancing said panels and stringers a predetermined distance through said releasable holding means when said holding means is released.
 13. An apparatus as defined in claim 12 wherein said releasable holding means comprises: a pair of shiftable plate members mounted in a framework; linkage means mounting said plate members for reciprocating movement; and actuator means connected to said plate members and said framework for moving said plate members toward and away from each other to secure said panels therebetween.
 14. The apparatus as defined in claim 13 and further including positioning means on said stringer support means; and means on said stringer support means and said positioning means for adjustably mounting same whereby said apparatus can be adapted to accommodate panels and stringer members of varying size.
 15. The apparatus as defined in claim 14 and further including auxiliary stapling means on said frame positioned adjacent said positioning means for securiNg a second pair of spaced-apart panels to a first plurality of stringer members when said stringer members exceed the length of said first-mentioned panels whereby said first-mentioned and said second spaced-apart panels will move together through said clamping and said fastening means to thereby form an elongated structural building unit. 